Apparatus for exposing core of an insulated wire

ABSTRACT

Apparatus for exposing the conducting core of an insulated wire comprises a pair of jaws movable relatively towards and away from each other between open and closed positions. Clamping means are provided on the corresponding ends of the jaws to clamp a wire extending between the jaws when the jaws are closed. The portion of the wire which extends between the jaws is loosely confined against substantial lateral flexure. Insulation pushing fingers mounted in the jaws are adapted to grip the insulation adjacent to the end of the wire and push it towards the clamping means. The insulation is bunched or compressed between the fingers and the clamping means and the end portion of the wire core which is thereby exposed for application of an electrical terminal.

United States Patent [72] Inventor James Woodrow Hammond Camp Hill, Pa.[2 I] Appl. No. 853,816 [22] Filed Aug. 28, I969 [45] Patented May 4,1971 [73] Assignee AMP Incorporated Harrisburg, Pa.

[54] APPARATUS FOR EXPOSING CORE OF AN INSULATED WIRE 7 Claims, 10Drawing Figs. [52] US. Cl. 8119.51 [5 1] Int. H02; 1/12 [50] Field 81/95 I 9.5 [56] References Cited UNITED STATES PATENTS 1,874,216 8/ I932Andrien 8 l/9.5I 2,929.285 3/1960 Gulemi 8 V9.5 1 3,044,334 7/ I962Broske 8l/9.5l

w13,s77,s14

Primary Examiner-Robert C. Riordon Assistant Examiner-Roscoe V. Parker,1r.

Attorneys-Curtis, Morris and Safford, Marshall M.

Holcombe, William Hintze, William J. Keating, Frederick W. Raring, JohnR. Hopkins, Adrian .I. LaRue and Jay L. Seitchik ABSTRACT: Apparatus forexposing the conducting core of an insulated wire comprises a pair ofjaws movable relatively towards and away from each other between openand closed positions. Clamping means are provided on the correspondingends of the jaws to clamp a wire extending between the jaws when thejaws are closed. The portion of the wire which extends between the jawsis loosely confined against substantial lateral flexure. Insulationpushing fingers mounted in the jaws are adapted to grip the insulationadjacent to the end of the wire and push it towards the clamping means.The insulation is bunched or compressed between the fingers and theclamping means and the end portion of the wire core which is therebyexposed for application of an electrical terminal.

Patented May 4, 1971 4 Sheets-Sheet 1 Patented May 4, 1971 4Sheets-Sheet 2 Patented May 4, 1971 3,577,814

4 Sheets-Sheet 3 Patented May 4, 1971 4 Sheets-Sheet 4 APPARATUS FOREXPOSING CORE OF AN INSULATED WIRE BACKGROUND OF THE INVENTION A widevariety of insulation stripping devices are commercially availablewhich, in operation, cut through the insulation of the wire adjacent tothe end thereofso that the end portion of the insulation may be strippedfrom the wire. Where the insulation is a conventional plasticinsulation, this method of stripping is highly successful. Most of theplastic insuiations which are presently used can be cleanly cut by theinsulation cutting knives and the severed section of the insulation canbe easily stripped from the wire end.

Certain types of insulated wire however, cannot be successfully strippedby the conventional stripping methods. particularly those wires whichare insulated with layers of loosely woven fabric or wires which areinsulated with batting and one or more layers of woven fabric. Forexample, one type of AWG [6 wire which is used where a high degree offlexibility is required has a conducting core of I04 very fine strandsand an insulating sheath comprising a plurality of layers of looselywoven cotton fabric. Wire of this type is widely used in installationswhere an extremely limp wire is required which can be bent throughextreme angles and which is required to undergo continuous or repeatedflexure during use.

When it is attempted to strip these fabric insulated wires with astripping mechanism having knives to cut through the insulation, it isdifi'icult, if not impossible, to obtain a clean cut through the layersof fabric because of the fact that the woven fabric yields, and iscompressed by, the insulation cutting knives. Furthermore, because ofthe limpness of these types of wires, it frequently happens that theinsulation cutting knives will cut into some of the strands of theconducting core which, because of their extremely small diameter, areeasily nicked and severed. Burning or singeing has been employed withsome success to strip wires of this type but this process is relativelyslow and the products of combustion of the singeing operation tend todeposit on the wire strands so that if a terminal is later crimped ontothe strands. an imperfect electrical connection may result.

It is an object of the present invention to provide an improvedapparatus for exposing the conducting core of a wire having insulationthereon of a type which cannot be easily removed by a conventionalcutting and stripping operation. It is a further object of the inventionto provide an improved apparatus for bunching or pushing the insulatedwire away from the wire end thereby to expose the end portion of theconducting core of the wire. A further object of the invention is toprovide an improved apparatus for exposing the conducting core of aninsulated wire of the type having one or more layers of woven cottonfabric thereon as the insulating material.

These and other objects of the invention are achieved in a preferredembodiment thereof which is briefly described in the foregoing abstract,which is described more fully in the description which follows, andwhich is shown in the accompanying drawings:

FIG. I is a perspective view of a typical fabric insulated wire.

FIG. 1A is a perspective view of the wire of FIG. 1 with portions of theseveral layers of insulation removed to reveal details of theinsulation.

FIG. 2 is a perspective view of an end portion of the wire of FIG. 1after the conducting core of the wire has been exposed in accordancewith the invention.

FIG. 3 is a perspective view of the wire of FIG. I having a terminalcrimped onto its exposed end.

FIG. 4 is a sectional side view of an insulation exposing apparatus inaccordance with the invention showing the position of the parts at thebeginning of the operating cycle with the jaws in their open positions.

FIGS. 5, 6, and 7 are views similar to FIG. 4 but showing the positionsof the parts at successive stages of the operating cycle.

FIG. 8 is a front view of the apparatus showing the position of theparts when the jaws are in their closed positions.

FIG. 9 is an exploded perspective view of the jaws of the apparatus ofFIG. 4.

The disclosed embodiment of the instant invention is directed to theproblem of exposing the conducting core of certain types of insulatedwires which cannot be stripped, or which are difficult to strip, byconventional stripping methods. Conventional stripping methods involvethe use of insulation cutting knives which cut the insulation so that itcan be removed. A typical type of wire which is not amenable toconventional stripping processes is shown at 2 in FIG. I to comprise aconducting core 3 containing a plurality of individual strands, and aplurality of layers 4, 5, 6, 8 of loosely woven cotton fabric. Wires ofthis type usually have a relatively large number of individual strandsin the core 3, for example, a typical AWG 16 wire having I04 individualstrands rather than the conventional 21 or 28 strands. The large numberof strands in the core coupled with the loosely woven fabric insulationrenders these wires extremely limp so that they can be flexed, bent,twisted, and otherwise manipulated without failure of the insulation orwork-hardening and eventual fracture of the strands of the core. Wiresof this type are used, for example, for ironing cords or for cords fordomestic appliances which are subject to a high degree of manipulation.

Wires of the type shown in FIG. I cannot be stripped by cutting throughthe insulation because of the fact that it is difficult to obtain aclean cut entirely through all of the insulation without damaging theconducting strands. The insulation is very soft and impressible and willreadily yield before the cutting knife. Furthermore, if the cut does notsever all of the fibers of the woven fabric, the remaining fibers willprevent removal of the partially severed end section of insulation.Finally, if the cutting knife should contact one or more of theindividual strands, there is a likelihood that the strand will besevered because of the fact that the strands are so very line.

In accordance with the instant invention, the end portion of theinsulating covering of the wire is pushed axially away from the wire endand bunched adjacent to the end as shown in FIG. 2. The exposed endportion of the conducting core can then be crimped onto a conventionalterminal as shown in FIG. 3. The terminal in this view has aconventional wire crimp portion I2 and an insulation crimp portion 14which are crimped onto the conducting core and the insulation of thewire respectively. The type of terminal shown also has a web 16 whichextends laterally from the two crimped portions, which is reversely bentat 18, and is formed on the underside of the terminal to provide areceptacle 20 for the reception of the rectangular tab. It will beunderstood that any desired type of terminal can be crimped onto theexposed core of the wire shown in FIG. 2.

Referring now to FIGS. 49, the disclosed embodiment of the invention isadapted to be mounted on a bracket 22 which in turn may be mounted on alead making machine of the type disclosed in U.S. Pat. application Ser.No. 814,361, as will be described below. The apparatus comprises abaseplate 24, secured to the upper surface of the bracket 22, a pair ofspaced-apart vertically extending sideplates 26, 28 which are secured tothe edges of the baseplate 24 and between which there is provided afixed lower jaw structure 32, and a reciprocable upper jaw structure 34.As best shown in FIG. 4, the sideplates 26, 28 are provided withrecesses 30 which extend inwardly from the front of the apparatus in thevicinity of the lower jaw to permit lateral movement of the wire to theposition between the jaws and lateral movement of the wire from the jawsafter exposure of the conducting core.

Referring particularly to FIGS. 4 and 9, the fixed lower jaw means 32comprises a support plate 36, the marginal edge portion of which arereceived within slots 37 in the opposed sides of the frame plates 26, 28and which is secured to the frame plate by suitable fasteners 38. Anaxially extending central rib 40 is provided on the upper surface of theplate 36, as viewed in FIG. 9, and a triangular block 42 having arectangular recess on its underside is fitted over this rib, the block42 being secured to the plate 36 by means of suitable screws whichextend through the screw holes 48.

A V-shaped recess 44 extends along the upper end of the triangular block42 intersecting the apex thereof and defining divergent sides.Additionally, spaced-apart projections 50 are provided on the sides ofthe block 42 and have edges 52 which are substantially coplanar with thedivergent surfaces of the V- shaped recess 44 of the block. Theseprojections cooperate with similar projections on the upper jaw toconfine the wire during movement of the jaws towards each other andduring the operation of the apparatus.

The insulation of the wire is grasped and pushed away from the wire endby means of a finger 54 in cooperation with the finger 54' on the upperjaw means. The finger 54 has an enlarged lower end which is receivedbetween a pair of spacedapart ears on the end of a reciprocable rod 60and the upper end of this finger is serrated as shown at 56. The lowerend is slotted at 63 and pivotally mounted on the end of the rod bymeans of a suitable pin 62. A torsion spring 64 surrounds the pin 62 andhas one arm which bears against the end of the slot 63 and another armwhich bears against the rod 60. This arrangement permits very limitedpivotal movement of the finger 54 so that it can adapt itself to therelatively soft compressible insulation of the wire during operation aswill become apparent as this description proceeds.

Rod 60 extends leftwardly as viewed in FIG. 4 through a bore 68 in theblock 36 and is connected at its left-hand end to a yoke arm 90described below. A slot 70 is provided in the rib 40 of the plate 36 anda slot 72 is provided in the block 42 intersecting the recess 44therein. The finger extends upwardly as shown in FIG. 4 through theslots 70, 72 so that its upper serrated end 56 is disposed between thesurfaces of the recess 44.

The upper jaw structure 34 comprises a plate 74 having a central rib 84on its underside which corresponds to the rib 40 of the plate 36. Ablock 75 is mounted on the underside of the plate 74, this block beingsomewhat similar to, although it is not identical to, the block 42 ofthe lower jaw structure. Thus the block 75 is generally triangular andhas a plurality of spaced-apart projections 78 on its sides which aredimensioned and spaced-apart such that they will be received between theprojections 50 of the block 42 when the jaws are in their closedpositions. It will also be noted that the apex of the block 75 isprovided with a V-shaped recess 76 which is complimentary to the recess44 of the block 42. Block 75 is secured to the underside of plate 74 bysuitable fasteners as shown.

The insulation pushing finger 54' of the upper jaw structure issubstantially similar to the pushing finger 54 of the lower jawstructure described above and is pivotally connected in the same manneras the lower pusher finger, to the rod 60'. This rod is slidablycontained in a bore 68' of the block 74 and the finger 54' extendsthrough aligned slots 70', 72 of the plate 74 and the block 75.

When the jaws are closed. the wire extending between the jaws is clampedby means of a pair of clamping plates 86, 86 which are mounted inrecesses 88, 88 on the right-hand ends of the plates 36, 74 as viewed inFIG. 4. The opposed ends of these clamping plates 86, 86' are serratedas shown at 90, 90' to assist in clamping the wire firmly during thewire core exposing operation.

The left-hand ends of the rods 60, 60' are pivotally connected to theyoke arm 90 which extends vertically through a slot 94 in a clevis block96 on the end of a piston rod 98 of a pneumatic piston cylinder I00. Theyoke arm is connected to the block 96 by means of a pivot pin 92 whichextends through a somewhat oversize opening in the yoke arm 90 to permitvery limited pivotal movement of the yoke arm relative to the block inorder to avoid jamming of the apparatus during rightward movement of therods 60, 60 from the position of FIG. 4 to the position of FIG. 6. Theconnection between the lower rod 60 and a lower end 106 of the yoke armis by means of reduced end 102 of the rod 60 having a slot whichreceives the lower end of the yoke arm, the parts being connected by apin 104. The upper rod 60' similarly has a reduced left-hand end 102'which is slotted for the reception of the yoke arm. The upper portion106' of the yoke arm, as viewed in FIG. 4, is provided with a verticallyextending slot I08 through which the pin I04 extends, the length of thisupper portion 106' being substantially greater than the length of thelower portion and being sufficient to permit downward movement of theupper jaw structure 34 from the position of FIG. 4 to the position ofFIG. 5. The pin I04 extends through the slot 108 thus pennittingdownward movement of the rod 60 with the upper jaw structure.

The upper jaw 34 is moved downwardly from the position of FIG. 4, to theposition of FIG. 5 by means of a pneumatic piston cylinder IIO, mountedon a suitable bracket I12, having a piston rod 114. A coupling block 116secured to the end of this piston rod extends into a central recess I18and a clevis block I20 which is disposed above the upper surface of theplate 74. A pin I22 extends through the clevis block, through thereduced lower end of the block 116, and extends laterally beyond thesides of the clevis block and into clevis plates I24 which are securedto the sides of the frame plate 74 of the upper jaw and secured theretoby suitable fasteners I26. The clevis plates I24 are slidably receivedin vertically extending recesses I32 in the opposed surfaces or frameplates 26, 28. It will thus be apparent that upon downward movement ofthe piston rod 114 from the position of FIG. 4 to the position of FIG.5, the upper jaw structure will be pushed downwardly to close the jawonto the wire. It is desirable to provide an auxiliary guide means forthe left-hand end of the upper jaw structure in the form of a verticallyextending slot I30 in the frame plate 26 and a guide member mounted onthe end of the plate 74 which extends into this slot. This auxiliaryguide means prevents any rocking of the movable jaw which mightotherwise lead to jamming of the parts.

In use, the parts will normally be in the position shown in FIG. 4. Thewire is positioned between the jaws with its end disposed approximatelybetween the opposed serrated ends of the insulation pushing fingers 54,54'. Compressed air is then admitted into the upper end of the pistoncylinder 110 thereby driving the piston rod II4 and the upper jawstructure 34 downwardly from the position of FIG. 4 to the position ofFIG. 5. As this upper jaw moves downwardly, the projections 78 of theblock 75 enter the spaces between the projections 50 of the block 42thereby confining the wire. As the upper jaw moves further downwardly,the surfaces of the V-shaped recesses 44, 76 move towards each other andthe projections 78 move further into the spaces between the projections50. At the end of the downward stroke of piston rod I14, the wire isconfined in a restricted corridor although it is not clamped orotherwise engaged by the surfaces and 52 of the projections. The wire isfirmly clamped by the clamping members 90, and the fingers 54, 54' arein firm engagement with the insulation adjacent to the end of the wire.Compressed air is then supplied to the left-hand end, as viewed in FIG.4, of the piston cylinder to cause the piston rod 98 and the rods 60,60' to move rightwardly from the position of FIG. 5 to the position ofFIG. 6. During such movement of the fingers, the insulation is pushedrightwardly and gathered or bunched between the fingers 54, 54' and theclamping members 86, 86'. The wire will tend to buckle during suchpushing of the insulation but will be prevented from buckling to anysubstantial degree by the surfaces 52, 80 of the projections 50, 78 andby the surfaces of the recesses 44, 76 of the blocks 42, 75.

After the insulation has been pushed rightwardly to the position of FIG.6, the core of the wire is exposed to the extent necessary to permitcrimping of a terminal onto the wire end. After the parts have reachedthe position shown in FIG. 6, the rearward ends of the cylinders "0. I00are exhausted thereby permitting upward movement of the piston rod I14and leftward movement of the piston rod 98. The movements of these twopiston rods can take place concomitantly and the wire can thereafter bemoved from between jaws to the crimping press. In the disclosedembodiment of the invention, the wire can be moved laterally into theapparatus to a position between the jaws and can, after exposure of theconducting core, be moved laterally to a crimping apparatus. Operationsof this type can be carried out conveniently on a lead making machine ofthe general type disclosed in U.S. Pat. application Ser. No. 8l4,36l, asdiscussed above.

It has been found in practice that wires having several layers, e.g.four layers, of fabric insulation can be processed in accordance withthe invention to expose a sufficiently long portion of the conductingcore to permit application of a contact terminal thereto. The insulationmay have some tendency to creep forwardly after it has been pushed backhowever, such creepage takes place relatively slowly and if the terminalis applied soon afier exposure of the core, a sufl'tciently long exposedsection will remain.

Some salient features of the invention include the clamping of theinsulation adjacent to its end. the confinement of the wire during theoperation of pushing the insulation away from the wire end. and finallythe provision of the fingers 54, 54' which bear against the surface ofthe insulation and compress it slightly while it is being pushed awayfrom the wire end. This effect is permitted by virtue of the fact thatthese fingers extend through the plates 42, which have the confiningmeans for the wire thereon.

While the invention has been disclosed herein with particular referenceto fabric and batting-type insulations which are not amenable toconventional cutting-type insulation-type stripping methods, it will beapparent that the principles of the invention can be used to expose theconducting core of various types of insulated wire having looseinsulation which cannot be stripped by conventional methods.

Changes in construction will occur to those skilled in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope of the invention. The matter set forthin the foregoing description and accompanying drawings is offered by wayof illustration only.

lclaim:

1. Apparatus for exposing the conducting core of the end portion of aninsulated wire comprising:

clamping and confining means for clamping said wire at a locationadjacent to its end and for confining the portion of said wire betweensaid clamping means and the end of sad wire against substantial lateralllexure,

insulation pushing and gathering means movable through said clamping andconfining means and towards said location, said insulation pushing andgathering means having insulation engaging means engageable with saidinsulation on opposite sides of said wire whereby, upon movement of saidinsulation gathering means towards said location, the insulation of saidwire is gathered away from the end of said wire and bunched between saidinsulation enpging means and said location thereby to expose the endportionofthe conductingcoreofsaid wire.

2. Apparatus for exposing the conducting core of an insulated wire co apair of jaw members movable relatively towards and away from each otherbetween open and closed positions,

said jaw members having clamping means at one end thereof to clamp aconductor extending therebetween when said jaw members are in saidclosed position, and said jaw members having opposed surface portionsdefining a confined passageway for said wire when said jaw members arein said closed position,

insulation pushing means movable through said passageway and towardssaid clamping means when said jaw members are closed whereby uponclosure of said jaw members into surrounding relationship with aconductor with concomitant clamping of said conductor and confinement ofthe end portion of said conductor in said passageway, and

upon movement of said insulation pushing means towards clamping means,the insulation ad acent to the end of said wire is gathered towards saidclamping means and bunched thereby to expose the end portion of theconducting core of said wire.

3. Apparatus as set forth in claim 2 wherein said insulation pushingmeans comprises a pair of fingers, one of said fingers being in each ofsaid jaw members.

4. Apparatus as set forth in claim 2 wherein said clamping meanscomprises a pair of clamping plates, one of said plates being mounted oneach of said jaw members.

5. Apparatus as set forth in claim 2 wherein said jaw members havespaced-apart projections on said opposed surfaces, the said projectionsof one of said jaw members being offset with respect to the projectionsof the other jaw member whereby said projections interdigitate duringmovement of said jaw members towards each other to define said confinedpassageway.

6. Apparatus as set forth in claim 2 wherein said insulation pushingmeans comprises a pair of fingers, one of said fingers being in each ofsaid jaw members, each finger being movably mounted in its respectivejaw member for movement towards said clamping means.

7. Apparatus for exposing the conducting core of an insulated wirecomprising:

a pair of jaw members movable relatively towards and away from eachother between open and closed positions, said jaw members havingclamping means at corresponding ends thereof for clamping a conductorextending between said jaws when said jaws are in said closed position,

conductor supporting and confining means on said jaw members inalignment with said clamping means, said conductor supporting meanscomprising supporting surfaces for supporting said conductor againstsubstantial lateral flexure, and

insulation pushing means in said jaw members, said insulation pushingmeans being movable relatively through said supporting and confiningmeans and towards said clamping means whereby upon clamping of aninsulated wire in said clamping means with its end portion extendinginto said supporting and confining mearu and upon movement of saidinsulation pushing means towards said clamping means, the end portion ofthe insulation of said wire is gathered towards said clamping means andthe conducting core of said wire is exposed.

1. Apparatus for exposing the conducting core of the end portion of aninsulated wire comprising: clamping and confining means for clampingsaid wire at a location adjacent to its end and for confining theportion of said wire between said clamping means and the end of saidwire against substantial lateral flexure, insulation pushing andgathering means movable through said clamping and confining means andtowards said location, said insulation pushing and gathering meanshaving insulation engaging means engageable with said insulation onopposite sides of said wire whereby, upon movement of said insulationgathering means towards said location, the insulation of said wire isgathered away from the end of said wire and bunched between saidinsulation engaging means and said location thereby to expose the endportion of the conducting core of said wire.
 2. Apparatus for exposingthe conducting core of an insulated wire comprising: a pair of jawmembers movable relatively towards and away from each other between openand closed positions, said jaw members having clamping means at one endthereof to clamp a conductor extending therebetween when said jawmembers are in said closed position, and said jaw members having opposedsurface portions defining a confined passageway for said wire when saidjaw members are in said closed position, insulation pushing meansmovable through said passageway and towards said clamping means whensaid jaw members are closed whereby upon closure of said jaw membersinto surrounding relationship with a conductor with concomitant clampingof said conductor and confinement of the end portion of said conductorin said passageway, and upon movement of said insulation pushing meanstowards said clamping means, the insulation adjacent to the end of saidwire is gathered towards said clamping means and bunched thereby toexpose the end portion of the conducting core of said wire.
 3. Apparatusas set forth in claim 2 wherein said insulation pushing means comprisesa pair of fingers, one of said fingers being in each of said jawmembers.
 4. Apparatus as set forth in claim 2 wherein said clampingmeans comprises a pair of clamping plates, one of said plates beingmounted on each of said jaw members.
 5. Apparatus as set forth in claim2 wherein said jaw members have spaced-apart projections on said opposedsurfaces, the said projections of one of said jaw members being offsetwith respect to the projections of the other jaw member whereby saidprojections interdigitate during movement of said jaw members towardseach other to define said confined passageway.
 6. Apparatus as set forthin claim 2 wherein said insulation pushing means comprises a pair offingers, one of said fingers being in each of said jaw members, eachfinger being movably mounted in its respective jaw member for movementtowards said clamping means.
 7. Apparatus for exposing the conductingcore of an insulated wire comprising: a pair of jaw members movablerelatively towards and away from each other between open and closedpositions, said jaw members having clamping means at corresponding endsthereof for clamping a conductor extending between said jaws when saidjaws are in said closed position, conductor supporting and confiningmeans on said jaw members in alignment with said clamping means, saidconductor supporting means comprising supporting surfaces for supportingsaid conductor against substantial lateral flexure, and insulationpushing means in said jaw members, said insulation pushing means beingmovable relatively through said supporting and confining means andtowards said clamping means whereby upon clamping of an insulated wirein said clamping means with its end portion extending into saidsupporting and confining means and upon movement of said insulationpushing means towards said clamping means, the end portion of theinsulation of said wire is gathered towards said clamping means and theconducting core of said wire is exposed.